“Bicycle” seems to be in reference to Albert Hoffman’s famous bicycle ride. Hoffman synthesized LSD-25 in November of 1938, but, because it did not have the intended effect of stimulating the circulatory and respiratory system, it remained on the shelf for five years.

However, on April 19th, 1943, Hoffman accidentally came into contact with an extremely small particle of LSD-25 and began to feel a change in his psychological and physiological state. Feeling woozy, he asked his lab assistant to escort him home. Since civilian cars were banned in wartime Germany, Hoffman and his assistant took the journey by bicycle, and it was during this bicycle ride that a human first experienced the psychedelic effects of LSD.

Bicycle Day is now celebrated annually on April 19th by psychonauts and drug enthusiasts, usually by imbibing the substance.